Generally, microwave ovens such as those illustrated in FIG. 1, heat objects (e.g., food) by applying microwaves to them. Referring to FIG. 1, the microwave oven includes a main body 10 including a front case 11, an outer case 12, and an outer frame 13, a cavity 20 in which an object may be heated by microwaves, and an electrical device chamber 30. The front case 11 forming the front side of the main body 10 includes a cavity door, which opens or closes the cavity 20. The outer frame 13 forms the lower and rear sides of the main body 10, and it protects the cavity 20 and the electrical device chamber 30 together with the outer case 12 and the front case 11. Microwaves may be generated by various electrical devices accommodated with the electrical device chamber 30 provided near the cavity 20. The various electrical devices may include, for example, a magnetron 31 for generating microwaves, a high-voltage transformer 32 for supplying high voltage to the magnetron 31, and a fan 33 generating an air flow inside the electrical device chamber 30 thereby cooling the various electrical devices as they may become heated.
While conventional microwave ovens heat objects using microwaves, microwaves cannot be used to toast food (e.g., bread products such as a slice of bread or bagel). Therefore, microwave ovens capable of toasting food as well as heating an object using microwaves have become desirable. In addition, the existing toasters often have problems when removing a food item. Therefore, microwave ovens incorporating a toaster that has a tray assembly which enables a user to easily insert and remove a food object into or from the toaster is highly desirable.